#version 450

layout (location = 0) out vec2 fragCoord;

out gl_PerVertex 
{
    vec4 gl_Position;   
};


void main () 
{
	vec2 pos[3] = vec2[3]( vec2(-3, 1), vec2(1, 1), vec2(1.0, -3) );
    gl_Position = vec4( pos[gl_VertexIndex], 0.0, 1.0 );
	fragCoord.xy = gl_Position.xy;
}